1. Field of the Invention
The present invention relates to production of electronic devices, and more particularly, forming organic material layers in electronic devices using a laser induced thermal imaging (LITI) technology.
2. Description of the Related Technology
Certain electronic devices include organic layers. For example, an organic light emitting device (OLED) includes various organic layers. Various methods have been used to form such organic layers. For example, such methods include a deposition method, an inkjet method, and a laser-induced thermal imaging (LITI) method.
In the LITI method, a film donor device is used to provide a transferable layer. The donor device is placed on a partially fabricated electronic device (intermediate device) such that the transferable layer contacts a surface (receiving surface) of the intermediate device on which the transferable layer is to be transferred. Then, a laser beam is applied onto selected areas of the donor device, which creates heat in the donor device in the selected area. The heat causes delamination of desired portions of the transferable layer. The delaminated portions of the transferable layer remain on the surface of the intermediate device when the donor device is removed.
A typical LITI apparatus uses suction to make and keep the transferable layer contact the surface of the intermediate device during this processing. FIG. 1 is a cross-sectional view of an LITI apparatus 100. The LITI apparatus 100 includes a chamber 110, a substrate support 120 and a laser source or oscillator 130. The substrate support 120 includes an intermediate device receiving groove 121 to receive an intermediate electronic device 140 therein and a donor device receiving groove 123 to receive a film donor device 150 therein.
To transfer organic material portions to the intermediate device with high precision and with fewer defects, a close contact between the transferable layer and the receiving surface is needed. The LITI apparatus 100 includes a suction mechanism to form such a close contact. The suction mechanism includes pipes 161 and 163 and a vacuum pump P. Suction through the pipes 161 brings and keeps the intermediate device (not shown) placed in the groove 121 down. Suction through the pipes 163 brings and keeps the donor device (not shown) placed in the groove 123 down and in contact with the intermediate device. To conduct these suctions, air or other gaseous medium is required within the chamber.
However, processes performed prior to or subsequent to the LITI process are typically carried out in a vacuum atmosphere. Thus, the LITI process using the suction described above needs to break the vacuum between the preceding and subsequent processes.
The discussion in this section is to provide background information of the related technology and does not constitute an admission of prior art.